In the prior art a feed circuit accepts a stream of digital payload data and inserts it at predetermined first positions into a stream of digital transmission data. In many cases the feed circuit feeds the thus obtained stream of digital transmission data directly into a transmission medium. The payload data will in that case be identical to the transmission data.
It is also already known that the feed circuit generates supplementary digital data using the stream of digital payload data, inserts said supplementary digital data, in addition to the digital payload data, at predetermined second positions into the stream of digital transmission data, and feeds the thus obtained stream of digital transmission data into the transmission medium. The stream of digital transmission data will in that case contain the payload data and the supplementary data. Typical processes are the generation of check information, for example parity bits, CRC (CRC=Cyclic Redundancy Check) information, and similar content. On the basis of the check information it is possible on the receiver side to detect and possibly even correct errors occurring during data transmission.
The transmission data is as a rule transmitted in the form of electric signals. In the case of line-based transmission the transmission medium corresponds to the transmission line; in the case of line-free transmission the transmission medium corresponds to an air link. Regardless of how the transmission medium is specifically embodied, transmitting of the transmission data may, though, have a disruptive influence on other equipment. For example other signals—in particular weak analog signals—can be disrupted. Magnetic resonance signals can be cited as an instance of weak, interference-sensitive signals of said type, but other situations are also conceivable in which transmitting of the digital transmission data can result in interference.
The interference is often especially critical when occurring at a specific frequency. In magnetic resonance systems it is, for example, particularly disruptive if the transmission data's spectrum includes components whose frequency corresponds to the Larmor frequency or another operating frequency of the magnetic resonance system or, as the case may be, is close thereto.
To avoid interference it is known how to shield the feed circuit, a corresponding feed-out circuit, and—in the case of line-based data transmission—the transmission medium. However, shielding of said type entails a substantial material outlay. It is further known how to locate potential sources of interference (which is to say the feed circuit, the feed-out circuit and, where applicable, the transmission medium) as far as possible from the elements that may be adversely affected. However, a solution of said type is awkward and not always practicable.